The invention relates to di- and trifluorotolans of the formula I: ##STR2## in which
R.sup.1 is alkyl having up to 9 carbon atoms, and
L is H or F.
Compounds of the formula I can be used as components of liquid-crystalline media, in particular, for displays based on the principle of the twisted cell, the guest-host effect, the effect of deformation of aligned phases, or the effect of dynamic scattering.
Compounds of the formula I are also preferably suitable for use as components in liquid-crystalline media for highly twisted TN displays (for example, 180.degree.-270.degree.), i.e., for STN displays.
Similar compounds are known from JP 61/260031, but the compounds according to the invention have favorable nematic phase ranges compared with the substances described therein. See also copending Application Ser. No. 07/623,385, filed Nov. 19, 1990, and the priority applications upon which it is based, DE 39 29 525.7 and DE 39 29 526.5, both filed Sep. 6, 1985; DE 39 29 764.0, filed Sep. 7, 1989; and DE 40 09 907.5, filed Mar. 28, 1990. See also GB 8,922,168.3, filed Feb. 10, 1989.